1. Field of the Invention
The present invention relates to a package changing system capable of changing packages efficiently with respect to a machine frame on which a large number of spindles for the change of empty and full-loaded packages are arranged in rows.
2. Prior Art
For example, in a double twister (two for one twister) for filament, a cheese-shaped package is wound back into a pirn-shaped package by means of a pirn winder, then the pirn is twisted twice and again wound into a cheese-shaped package. The change of package in such a double twister for filament is performed in the following order, 1-5. 1 Take out a tenser unit from an empty pirn, 2 take out the empty pirn, 3 mount a full-loaded pirn and 4 attach a tenser unit to the full-loaded pirn. 1 to 4 are concerned with the change of empty and full-loaded pirns. Then, 5 a full-loaded bobbin (hereinafter, a package at the winding side of a double twister is referred to as a bobbin) and an empty bobbin are replaced with each other.
The above changing operations 1 to 5 inevitably involve the conveyance of empty pirn, full-loaded pirn, empty bobbin and full-loaded bobbin. The conveyance system practically used in the double twister for spun yarn may be effective for automating such changing operations 1 to 5 and conveyance. According to the said conveyance system, a conveyor for the supply of full-loaded pirns and for the recovery of empty pirns and a conveyor for the discharge of full-loaded bobbins are used in cooperation with a doffing device capable of traveling around a machine frame to perform the changing operations 1 to 5.
However, since the doffing cycle in the double twister for filament is as long as 3 to 20 days, it is necessary to provide a conveyor for each machine frame, and the provision of a doffing device causes an increase of instrumental waste. In the double twister for filament, moreover, spindles are arranged in two vertical stages in many cases, so the use of a dolling device or the like results in the machine height become too large.